genai: add WithClientInfo client option (#159)

Add an option that lets  products identify which calls
are made with this client.

genai/client.go

@@ -87,7 +87,15 @@ Import the option package as "google.golang.org/api/option".`)
  if err != nil {
  return nil, fmt.Errorf("creating discovery client: %w", err)
  }
- gc.SetGoogleClientInfo("gccl", "v"+internal.Version, "genai-go", internal.Version)
+
+ kvs := []string{"gccl", "v" + internal.Version, "genai-go", internal.Version}
+ if a, ok := optionOfType[*clientInfo](opts); ok {
+ kvs = append(kvs, a.key, a.value)
+ }
+ gc.SetGoogleClientInfo(kvs...)
+ mc.SetGoogleClientInfo(kvs...)
+ fc.SetGoogleClientInfo(kvs...)
+
  return &Client{gc, mc, fc, cc, ds}, nil
 }
 

genai/client_test.go

@@ -865,3 +865,16 @@ func uploadFile(t *testing.T, ctx context.Context, client *Client, filename stri
  })
  return file
 }
+
+func TestAttribution(t *testing.T) {
+ a := WithClientInfo("k", "v")
+ opts := []option.ClientOption{option.WithAPIKey("x"), a, option.WithEndpoint("e")}
+ got, ok := optionOfType[*clientInfo](opts)
+ if !ok {
+ t.Fatal("not found")
+ }
+ want := a.(*clientInfo)
+ if got.key != want.key || got.value != want.value {
+ t.Errorf("got %q, %q, want %q, %q", got.key, got.value, want.key, want.value)
+ }
+}

genai/option.go

@@ -0,0 +1,44 @@
+// Copyright 2024 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package genai
+
+import (
+ "google.golang.org/api/option"
+ "google.golang.org/api/option/internaloption"
+)
+
+// WithClientInfo sets request information identifying the
+// product that is calling this client.
+func WithClientInfo(key, value string) option.ClientOption {
+ return &clientInfo{key: key, value: value}
+}
+
+type clientInfo struct {
+ internaloption.EmbeddableAdapter
+ key, value string
+}
+
+// optionOfType returns the first value of opts that has type T,
+// along with true. If there is no option of that type, it returns
+// the zero value for T and false.
+func optionOfType[T option.ClientOption](opts []option.ClientOption) (T, bool) {
+ for _, opt := range opts {
+ if opt, ok := opt.(T); ok {
+ return opt, true
+ }
+ }
+ var z T
+ return z, false
+}